Presentation Authors: Yasuhiro Hashimoto*, Hayato Yamamoto, Atsushi Imai, Shingo Hatakeyama, Takahiro Yoneyama, Chikara Ohyama, Hirosaki, Japan
Introduction: High endothelial venules (HEV) are present in lymph nodes and tertiary lymphoid organs. It has been reported that HEV density is associated with tumor aggressiveness of several carcinomas.MECA 79 antibody recognizes L-selectin ligand (6-sulfo sialyl Lewis X glycan) expressed in HEV. In the present study, we examined MECA79 (+) HEV density in pheochromocytoma.
Methods: Thirty-three patients with pheochromocytoma who underwent surgical treatment at the Hirosaki University hospital between January 2005 and December 2016 were enrolled. Tissue microarray for MECA 79 was performed, and HEV densities were calculated. HEV density < 1.5/mm2 was defined as HEV (-); HEV density â‰¥1.5/mm2 was defined as HEV (+). We also conducted immunohistochemistry of MIB-1 and calculated MIB-1 index.
Results: Of 33 patients, 13 (39.3%) were male and 20 (60.6%) were female. The average age was 56.1 years (range, 12-78 years). The mean observation period was 74.4 months. Of 33 cases, 3 cases (9.1%) were malignant pheochromocytoma. In our cohort, five cases (15.1%) were found to be HEV (+). The mean HEV density was 1.84/mm2. (0-20.8) Interestingly, of HEV (+) five cases, three cases were malignant pheochromocytomas. HEV density was significantly different between malignant pheochromocytoma (17.60 Â± 2.44/mm2) and pheochromocytoma (0.26 Â± 0.18/mm2, non-paired t-test: p < 0.0001). However, MIB-1 index was not significantly different between malignant pheochromocytoma (2.27 Â± 0.61 %) and pheochromocytoma (1.69 Â± 0.19 %, non-paired t-test: p=0.359).
Conclusions: In the present study, MECA79 positive HEV density may be associated with tumor aggressiveness of pheochromocytoma. Despite the small sample size and preliminary nature of our study, our study provides valuable insights to guide future research.